HowTo speed-compare various disks and storage media (aprox. real use test)

1. Check the speed of USB/SDHC disk

Is your USB/SDHC disk really fast for your PC/O.S.? The drive by itself could have an enormous specification read/write speeds over 15MB/s) but it is better to know the actual data throughput on the target PC using the ext2 or fat32 filling system. There is always a possibility your card reader (especially on SDHC cards) to be slower than the card's specification.

You can make your own "benchmark" creating a big directory (at least 1GB) containing various files from small .txt to giant .zip or iso images. For my tests I used a total of 25 files (5x23MB kernel images, 1x698MB Ubuntu .iso, 1x462 lxde .img, 1x1.4MB wvdial zip and some small .pdf and .txt files). Total size 1200MB.

Format your USB/SDHC disk on ext2 or FAT32 using GParted. For speed use ext2 and for compatibility (I am not sure!) with windows use FAT32. BE CAREFUL while formating/partitioning to select the USB/SDHC disk and not other drive! You can destroy your data! Also make a copy of files into USB/SDHC drive as they are going to vanished.

Attach the formated USB/SDHC drive to an Ubuntu running PC, after mounting you are going to create 2 directories (G_various & G_var in my example) and start timing the copy operations. You should know also where the "big directory" is located (/home/g/Desktop/G_various in my example). Also you need to know the name of the USB/SDHC disk (JF_ext2 in my example).

Open a terminal window:
sudo mkdir /media/JF_ext2/G_various
sudo mkdir /media/JF_ext2/G_var

TIP: typing a command or a directory/file name you can use TAB to auto fill the rest of the name (if there is more than one possible options the system will list them. This is not the T9 from your mobile phone but the smarter T0!)

time sudo cp -r /home/g/Desktop/G_various/* /media/JF_ext2/G_various
time sudo cp -r /media/JF_ext2/G_various/* /media/JF_ext2/G_var

The first "real time" shows the duration for the copy FROM your running system (usually HardDisk) TO the USB/SDHC disk.
The second "real time" shows the duration for the copy FROM/TO the USB/SDHC disk.

>>> You can repeat above to find the fastest one (till you get tired). Divide total size of the directory (in MBytes) by the time duration (in seconds) and the  result is MB/s. Compare only "same type" of tests. Copying from memory or HardDisk to the USB/SDHC disk is not the same as copying data from/to the same media.


Still under construction...

http://acomelectronics.com/GeorgeVita/Gdsk_bnch.txt